Use of atmospheric plasma treatment to improve adhesion properties of sodium ionomer sheets

Polyolefins are characterized by having a low surface energy due to their non-polar nature, in the case of some ionomers, the base component is a polyolefin, thus relative poor adhesion properties are expected. As is widely known, for many industrial applications, such as coatings, paintings and formation of adhesive bonds, a high surface energy is required in order to provide good surface adhesion; for this reason the use of ionomers in these applications requires a previous surface treatment. In this paper surface treatment by atmospheric plasma has been used to provide surface activation to polyolefin-based sodium ionomers in order to improve their low intrinsic adhesion properties. This work has focused on the analysis of the influence of main process variables such as treatment rate and distance between nozzle and substrate to observe the improvement of adhesion properties at ionomer–polycarbonate adhesion joints subjected to shear and T-peel tests. After plasma treatment, T-peel force has increased six times it original value at most aggressive plasma parameters. Regarding on shear force, at same aggressive conditions of plasma treatment we achieved an increase of ten times its value of the shear sample without surface treatment, and its phenomenon can be seen in SEM pictures.